Flysky Noble NB4+ 2.4GHz 8CH Radio TX, RC Transmitter with FGR4B RC Receiver, AFHDS 3 Protocol - Remote Controller, Surface RadiTo attach the base: 1. Line up the base so that the transmitter handle has a slight over hang on the back. 2. Carefully insert the base contacts into the hole in the bottom of the handle. 3. Hold the handle firmly and pull the battery backwards. When it is secure you should hear a click. Transmitter Specifications (Noble NB4+) Product model: Noble NB4+ Adaptive Receivers: FGr4B and other AFHDS 3 receivers Adaptive Models: Car or Boat Number of